Abrasive sleeve holder



A gl954 G. A. LARSON I 2,687,601

ABRASIVE SLEEVE HOLDER Original Filed Feb. 23, 1952 V IRVIIZU7 Geomeflla sory Atg.

Patented Aug. 31, 1954 ABRASIVE SLEEVE HOLDER George A. Larson, Rockford, 111.

Original application February 23, 1952, Serial No.

273,061. Divided and this application September 25, 1953, Serial No. 382,246

2 Claims.

This application is a division of my copending application, Serial No. 273,061, filed February 23, 1952.

This invention relates to a rotatable wheel-like holder for an abrasive sleeve in the form of an endless flexible band. The present improvements are concerned with the holder itself. It is produced mostly, if not entirely, from a resilient material, such as rubber (synthetic, natural, or mixed), with capacity for radial expansion in response to the centrifugal force that arises from rotation. The sleeve fitted around the periphery of the holder is, in consequence, subjected on its imier face to an outward expansion of the holder sufficient to tension the sleeve and secure it fixedly in place.

The present holder utilizes a roller body of rubberlike material formed with a plurality of symmetrically arranged holes which extend tlierethrough in a direction parallel with its axis. These holes are sized and spaced so as to provide between them solid webs which stretch or compress according to whether the holder is in motion or at rest. When an object is pressed against the sleeve, the holder will tend to yield inwardly, counter to the centrifugally developed force of expansion. By the improved construction disclosed herein, the yieldability of the holder is controlled so as to avoid relatively hard and soft spots at different points in its periphery.

My invention aims to produce a circular holder of the kind described which, although yieldable in response to pressure from the work, provides a substantially constant resistance at all points. It also aims to accomplish this objective by means which is simple and inexpensive and long-lived, and in which there is ample aeration to maintain a relatively cool condition of the holder. The holder itself consists of a one-piece roller, produced by a molding operation or otherwise, so as to involve the minimum of expense in its manufacture.

In the accompanying drawing:

Fig. 1 is a view in end elevation of the holder, and

Fig. 2 is a fragmentary view showing a localized displacement of the holder body in response to peripheral pressure applied in the direction of the arrow.

The same reference numerals are applied to corresponding parts in these two views.

The holder H is in the form of a roller body having a diameter that is suitable for supporting therearound a sleeve S of predetermined peripheral length. The length of the holder axiswise corresponds generally with the width of a conventional sleeve, perhaps an inch or two. In the holder is a center hole which may be occupied by a bushing B arranged for fitting upon a supporting rotary spindle (not shown) whereby rotation is transmitted to the holder and to the sleeve carried thereby.

The circular holder body is formed of a suitable rubber-like material. This is desirably a relatively soft rubber-natural, synthetic, or otherwise. When rotated, centrifugal force produces a radial expansion of the holder body, tending to enlarge its diameter; when at rest, the holder body contracts again to its normal size.

To control the expansive movements of the holder body so as to maintain a substantially uniform condition of yieldability at every peripheral point is one of the principal objects of this invention. I accomplish this by providing a plurality of holes extending through the holder parallel to its axis. These holes are arranged in circular rows concentrically of the holder axis, those in the inner row designed as i, being all of one size, whereas those in the outer row, designated as o, are all of another size. The holes 2 in the inner row are somewhat larger than those in the outer row, but are fewer in number by onehalf. As herein shown, nine holes 2 in the inner row are provided, and eighteen holes o in the outer row, the diameters of the former being greater by about one-third. All of the outer holes 0 are spaced equidistantly apart as are also the inner holes 2, and each two adjacent outer holes are also spaced the same distance away from one of the inner holes i so that all the radial lines 22 passing through the centers of the inner holes lie equidistantly between the proximate pairs of outer holes.

Slots x which extend tangentially outwardly from the outer'holes 0 open out upon the periphery of the holder body H. Each slot is also tangential to a circle t concentric with the axis of the holder. The radius of this circle, shown in dotted lines, is desirably more than one-fourth the radius of the roller body and less than that which is sufficient to touch each of the inner holes 1'. The slots :0 are accordingly disposed slantwise of the radial lines 55 to cut across the spokes defined by each of the webs b, thereby producing a lateral deflection thereof.

In operation, the holder is revolved at a normal speed, as 1700 R. P. M., and a piece of work is held in pressure engagement with the sleeve S which is fitted around the holder to revolve therewith. The outer face of this sleeve carries a coating of abrasive material which contacts the work. The pressure applied by the work against the sleeve is often very considerable and also 10- calized, and it is desirable that the holder body yield somewhat in response thereto. This yielding by the present holder body is so controlled that a uniform and even resistance is maintained at every peripheral point. The holder body 3 should have this capacity for such yielding so that the sleeve may tend to flatten somewhat at the point where pressure is applied, particularly when the work face undergoing treatment is relatively flat.

With pressure exerted against the outer face of the sleeve, the holder will accordingly yield, and, in so doing, parts of its body structure will be displaced somewhat, as indicated in Fig. 2. Since the peripheral speed of the sleeve is quite fast, it is manifest that the radial lines 2 -2 and 3-3 follow each other, and others in between, in rapid succession past the point of force application. The inward displacement of the holder body produces an ellipticity of each outer hold with its long axis disposed transversely of the intersecting radial line. The webs 1) between adjacent pairs of outer holes resist this deformation and are backed up by the inner webs a at certain points, and by other webs c which join the bases of the intermediate webs b with the continuous spokes defined by the next adjacent aligned webs a and b. This displacement of the web structure of the holder at the peripheral point where a force is applied to the sleeve also produces an ellipticity of each inner hole 2'. At each such point a lateral displacement of the adjacent inner webs a also takes place.

It is difficult to utilize a circular solid body of resilient material for an abrasive sleeve holder due to excessive weight and temperature generated in use. The provision of holes through the body to reduce this weight and temperature condition has not been satisfactory in the past, due to imbalance of the holder body and weakening of its structure with resulting nonuniformity in its resistance to yielding when a localized pressure is applied to its periphery. By the means herein described, however, these deficiencies of the past have been overcome. This results in part from the provision of inner and outer circular rows of holes, arranged concentrically of each other and of the circular holder body, with the inner holes the larger but only one-half the number of the outer larger holes, the peripheral portion of the holder body being preserved continuous and unbroken; the holes so arranged are spaced apart substantially equidistantly from each other in the same row and from those in the other row; and between adjacent holes in the inner row are stretchable webs which are aligned with other stretchable webs between adjacent pairs of holes in the outer row, the remaining in-between webs between adjacent holes in the outer row being disposed radially oppositely 0f the holes in the inner row. The body structure so produced is light, well aerated, and deformable in response to a localized pressure at its periphery with a substantially uniform yieldability at every point whereby its abrasive sleeve is enabled to operate more efiectively upon the work.

When work engages the sleeve that is carried by the holder, the resulting inwardly directed radial pressure produces in the peripheral portion of the holder a local lateral displacement that is mainly in the direction the same as that in which the holder is rotated. This is possible both because of the space existing between opposite walls of each slot m into which one wall may freely move, when displaced, and to the reduced resistance to such movement at the point where the slot is formed. As a result, there is increased resiliency in the outer peripheral portion of the holder which augments both its expansibility,

under rotation, and its yieldability when subjected to inwardly directed radial pressure from the work.

It is believed the foregoing description conveys a good understanding of the objects and advantages of my invention. The appended claims have been drawn to cover all legitimate modifications and adaptations.

I claim:

1. A rotary one-piece expansible sleeve holder of rubber-like material in the form of a roller, the roller body being formed therethrough with a plurality of circular holes extending between its opposite ends and arranged in at least two concentric circular rows with the holes in each row arranged in equally circumferentially spaced relation, the cross-sectional area of the holes in the outer row bein alike and small in relation to the cross-sectional area of the holes in the inner row, and the number of holes in said inner row being but one-half the number of those in said outer row, the arrangement being such that the webs between adjacent holes in said inner row are aligned with webs between adjacent pairs of holes in said outer row with the remaining inbetween webs between adjacent holes in said outer row disposed radially opposite the holes in said inner row, there being a slot extending through the roller body from each hole in the outer row, tangentially thereof, and toward the outer periphery of the roller body to open out thereupon, each slot being disposed tangentially of a circle concentric with the axis of the roller and of a radius less than that of the inner circle of holes in the roller body and defining between each pair of adjacent slots a section which is displaceable independently of the remaining sections and laterally in a predetermined direction.

2. A rotary one-piece expansible sleeve holder of rubber-like material in the form of a roller in which the rubber-like body constitutes at least the major portion of the radius of the roller, the roller body being formed therethrough with a plurality of holes extending between its opposite ends and arranged in at least two concentric circular rows, the holes in the outer row being in equally circumferentially spaced relation, the cross-sectional area of the holes in the outer row being alike and small in relation to the crosssectional area of the holes in the inner row, there being twice as many holes in the outer row as in the inner row and the holes in the inner row being located with their centers on radial lines passing midway between two adjacent holes in the outer row, the holes in the two rows being spaced so that the webs between the holes in the outer row and the periphery of the roller are substantially equal in thickness to the webs between the holes in said outer row and substantially equal in thickness to the webs between the holes in the outer and inner rows, there being a slot extending through the roller body from each hole in the outer row, tangentially thereof, and toward the outer periphery of the roller body to open out thereupon, each slot being disposed tangentially of a circle concentric with the axis of the roller and of a radius less than that of the inner circle of holes in the roller body and defining between each pair of adjacent slots a section which is displaceable independently of the remaining sections and laterally in a predetermined direction.

No references cited. 

